Railway Bogies

ABSTRACT

This invention relates to a bogie ( 10 ), including a load bearing point ( 11 ), a wheel set portion ( 12 ) and an intervening spring suspension ( 13 ). A load weigh valve ( 15 ) is fixed between the load portion ( 11 ) and the spring ( 16 ) of the suspension ( 13 ). The valve ( 15 ) is mounted within a wedge element ( 19 ) so that it continually measures the vertical load.

This invention relates to railway bogies.

In existing railway bogies it is known to provide load weigh valvessitting atop suspension springs, such that they are positioned betweenthe sprung mass of the bogie and wagon and the unsprung mass of thewheel set. The load weigh valve is held in a fixed location on the bogieframe, whilst the sprung mass generally moves vertically upwards anddownwards in a fixed vertical z-plane. In this configuration the loadweigh valve measures a proportion of the sprung mass via the springforce, which is a constant for a given load. However any verticalmisalignment or horizontal relative movement in the X and Y planesbetween the unsprung mass and the sprung mass, for example, as a resultof wheel set steering, can lead to inaccuracy in the resulting absoluteamount of braking load, which is applied proportionally to the output ofthe load weigh valve.

From one aspect the invention consists in a wheel set, a suspension forsupporting the load on the wheel set, the suspension including at leastone spring mounted on the wheel set, a wedge element for locationbetween the load and spring to accommodate changes in vertical alignmentbetween the load and wheel set and a load weigh valve for providing anindication of the mass of the load as applied to the springcharacterised in that the load weigh valve is mounted between the springand the wedge element.

As the load weigh valve is now not fixed in vertical alignment, butmoves with the wedge element, for example when the bogie steers in the Xand Y planes, with the frame, the errors provided by the previous systemeither do not arise or are substantially mitigated.

Preferably the load weigh valve is mounted on the wedge element formovement therewith and conveniently the wedge element may define achamber, for example the wedge element may be hollow, and the load weighvalve may be mounted therein.

The invention also includes a railway vehicle having at least two bogiesas defined above and wherein one bogie has at least a forward inclinedwedge element and the other bogie has at least a rearward inclined wedgeelement and the load weigh valves may be respectively on the forward andrearward inclined elements.

A vehicle may further include a computing device for computing a meanindication from the respective indications of the load valves. In thiscase it may additionally include a controllable braking systemresponsive to the mean indication.

Although the invention has been defined above it is to be understood itincludes any inventive combination of the features set out above or inthe following description.

The invention may be performed in various ways and an embodiment will bedescribed, by way of example, with reference to the accompanyingdrawings in which

FIG. 1 is a cross-sectional view through part of one end of a bogie of aprior art arrangement; and

FIG. 2 is an equivalent view of an embodiment of the invention; and

FIG. 3 is a schematic view of part of a railway vehicle having twobogies.

FIG. 1 illustrates a known bogie suspension arrangement. The bogie, partof which is shown at 10, includes a load bearing portion 11, a wheel setportion 12 and intervening spring suspension 13. The load portion 11 andwheel set portion 12 are designed to move vertically with respect to oneanother, this movement being defined by inter-engaging faces, which aregenerally indicated at 14.

A load weigh valve 15 is fixed between the load portion 11 and a spring16 of the suspension 13 by means of plates 17 and 18 and at theinterface 17 a, by means of screw fastenings.

As previously indicated this arrangement works well when there is truevertical movement, but the spring 16 may be required to tilt in the Xand Y plane, for example when the bogie is cornering but with a fixedand unmovable valve, and this leads to the errors previously described.

Turning to an embodiment of the Applicant's design as shown in FIG. 2,the major difference, for present purposes is that the interface 17 a isreplaced by a wedge element 19 which bears on an inclined friction plate20 to allow fore and aft and lateral movement of the wheel set 12relative to the portion 11, whilst allowing the spring to maintain itsvertical orientation. It will also be noted that a correspondingrearwardly inclined wedge and friction plate combination are shown at 19a and 20 a respectively.

In this arrangement the wedge element 19 can be hollow to define achamber within it and the load weigh valve 15 is mounted in the chamberfor movement with the wedge element 19, so that it continually measuresthe vertical load.

In practice, railway vehicles, as is schematically shown at 21, have atleast two bogies 10 and 10 a. In this case load weigh valve 15 may bemounted on a rearwardly inclined wedge element 19 a on one bogie and onthe forwardly inclined wedge element, 19 on the other bogie. The outputsfrom these two load valves can be fed to a control device 22, whichproduces a mean of the two readings and uses this to generate a controloutput for a braking system 23, which controls the braking on the bogiewheels 24.

1. A railway bogie including, wheel set, a suspension for supporting aload on the wheel set, the suspension including at least one springmounted on the wheel set; a wedge element for location between the loadand spring to accommodate changes in vertical alignment between the loadand wheel set and a load weigh valve for providing indication of themass of the load as applied to the spring characterised in that the loadweigh valve is mounted between the spring and wedge element for movementwith the wedge element.
 2. A railway bogie as claimed in claim 1 whereinthe load weigh valve is mounted on the wedge element for movementtherewith.
 3. A railway bogie as claimed in claim 2 wherein the wedgeelement defines a chamber and the load weigh valve is mounted therein.4. A railway vehicle having at least two bogies as claimed in claim 1and wherein one bogie has at least a forward-inclined wedge element andthe other bogie has at least a rearward inclined wedge element and; theload weigh valves are respectively on the forward and rearward inclinedelements.
 5. A vehicle as claimed in claim 4 further including a controldevice for providing a mean indication from the respective indicationsof the load weigh valves.
 6. A vehicle as claimed in claim 5 including acontrollable braking system responsive to the mean indication.